Safety device for elevators.



E. A. SMITH.

SAFETY DEVICE PoE ELEvAToEs. APPLIOATIONIILED FBBJ, 1905.v

1,132,744.. .Patented Mar'. 23, 1915.

L.0 o /,//-?6'/J'/ f/ f Z/A z Y WITNESSES: INVENTOE L I EMME- LAM wg BYTHE MORRIS PETERS CO., FHDTo-LITHO.. WASHINGTON. D. L

* Unir ears i EDWARD A. SMITH, or NEW YORK, N. Y., assIGivoR To oTisELEVATQR coiviraivn r `CORPORATION 0F NEWUERSEY.

l SAFETY DEVICE FOR ELEVATORS. Y

To all whom it may concern Be it known that linwannv A. SMITH, a citizenof the United States, residing at New York city, in the county-vof Newa'ork and State of New York, have invented certain newl and usefulImprovements in Safety Devices for Elevators, of which the following isa specicaticn.

My invention relates to a safety device for elevators and its Objectistoiinprove upon structures of this kind now in use and to` provide adevice for quickly andv positively clamping an elevator car to theguidesove which it is ladapted to run. Y

I lwill describe my invention inthe following specification and pointout the novel features thereof in claims.'

Referring'tothe drawings, lFigure 1 is a diagrammatic view in elevationof an eleva-V tor car and certain connected apparatus which is used incarrying out my invention.`

Fig. 2 is a plan view, partly in section, of my safety device, showingsections ofthe guides which it is intended to clamp. Fig.

3 is a plan view of a mcdiiication of my'device. Figs. 4 and 5 show-twoother modificationsof my invention. Fig. 6 is an en-A tom of which mydevice is attached.

11 is a hoisting rope for the car.l p 12 is a governor rope connected torun with the car. This governor rope runsunder a sheave 13 situated nearone end of.

the cars travel. It may be weighted, as at 15, and pawls 16, 16 may beprovided if de sired and radapted to engage with ratcliets in the sidesyof the weight to prevent its up- Y.

ward movement.v The governor rope 12 runs over another sheave 14 nearthe other end of the cars travel, which is connected to a governor'orspeed regulator 17 by suitable gearing 18. The speed governor isarranged to actuate a gripping device 19 which grips and Vpositivelylocks the governor rcpe when the car runs A'in excess of normal speed.It `may be arranged to op-- crate when the car is running in either di-Y rection. The governor rope, is yieldingly connected to the car at 12and is so arranged i i that when the lgovernor rope l2 isv stopped 4Specification of Letters Patent. Pattedlwrtgg"1915.appiicauonsiearebruary 6,1905. seriaiivaaeinci. 'i l impait a rotarymotion to the winding drum 3l. It is sometimes desirable to rotate ,the

winding drum 31 by handl frcin the car, and for this purpose Iprovideanother rope 12C on the winding druml and attach to this rope ahandle 12D- withinreach' ofthe operator in V the car.

i Wai now referto Fig. 2 and fiesen-be are 'I clamping device `or safetydevice for the elevator car which is there illustrated. yThe Windingdrum is rotatably4 mountedfuponhubs 35, 35 on rigid brackets 34', -34..The p l Y l l drum may be grooved as shown at 32 for the reception of.'the' rope '125,.and vseparate grooves 33 may be added if desired forthereception of the rope 12C. `The inside lof the drum vis bored cut'toyreceive two, shafts-36, 36, the outer ends of which arethreaded oneV,with a left hand threada'nd theother'with Y i a right handthread.Feathers 436, 36 are'` provided which engage with the drum and Vtheshafts, so that the shafts will turn" with 3 V the drum but are 'atthe-saine timeY freeto move longitudinally. The threadedendsof-A ktheseshafts, one of which 3Tis'shown in the drawing, run through collars 38,38 which are threaded on theinside to i'it the threads von the 'shafts36. The collars 38 'are also i threaded on the outsidewith right andleft.y

`hand threads respectively of liigher-'pitch ywhich fit into similarthreads inthe rigid l 1 brackets 34, Thus the collars 38, 38

form dier'ential screws each having a highpitch thread and a low'pitchthread.

, Wherever I use the expression reasons which will be pointed outlater.' Near the ends of the shafts 36, 36, collars are -105 providedasfshown at '39;v Vedge-shaped cams 25, 25 lz irearrang'ed to belmovedjby the collars 38 andthe 36 between ant-ifl y raro. g

ioo

friction rollers 24, 24. These rollers areon the ends of the jaws 21,2l`of a clamping device. The jaws 21, 2l are pivoted/ at '23 and arearranged to be moved into engagei Collars. rFliese by reason of theirhigh pitch will cause the cams 25, 25 to be quickly pushed apart andbetween the rollers 24, 2% until the jaws 2l, 21 are brought intocontact with the guides 22, 22. The further movement of the sleeves 3S,33 will then be resisted by the back pressure on the cams 25 and theywill move no farther, but the continued movement of the shafts 36 willnow push the low pitch threads 37 through the collars and theywillcontinue to move the cams 25, 25 between the rollers 241A, 24. at lessspeed but with greater power and so cause the clamping device to betightened firmly on the guides 22, 22. rlhis will be `continued untilthe. car is brought to rest vends of the sleeves 38.

thereby, when the movement of the drum 3l will cease. rl`he peculiarshape of the high pitch threads on the outside of the sleeves 38 willprevent the latter being pushed back bythe back pressure on the cams 25,25 because their long sloping sides will be in effectrwedged into thecorresponding sides of the internal threads in the brackets 3l, 34.TWhen, however, it is desired to release the clamping device from theguides, the drum 3l` may be turned back by hand or otherwise, the lowpitch threads will work back into the sleeves38, 3S until the collars39, 39 which are secured to their respective shafts abut the sleeveswhenthey will be moved back to their original positions. lf desired,springs 21A, 2lA may be provided to move the jaws 2l, 2l away from theguides when the cams 25, 25 are drawn back.

lt should be noted that when the high pitch and low pitch screws arere-set so that the low pitch screws will work back into the sleeves 38,'33, until the collars 39, 39 abut the outer ends of the sleeves the highpitch screws and low pitch screws will be clamped together. That is tosay, not only Y is the sleeve 3S held on the screw 37 by friction at thescrew threads but also by friction between the collars 39 and the outerrThe arrangement may thereforebe such that when the clamping jaws meetresistance not only must the friction of the low pitch screw threads loeovercome but also the friction at 'the clamp` mg connection between thecollar 39 and the outer end of the sleeve 38.

In the modification shownin Fig. 3, a

single high pitch and low pitch screw is shown at 38 and 37which willwork in a yoke or frame 30. Ilhey are arranged to be actuated as m theformer case by a winding drum 3l and to apply clamps 21',

2l', to the guides 22, 22, in this case by means of levers 26, 26, ofwhich said clamps form an integral part. These levers 26, 26, arepivoted together and to the frame 30 Fig. 4 shows another modificationin which instead of high pitchthreads, the cam surfaces Lit), 40 areattached to the drum and are arranged to co-act with similar surfaces41, 4l on collars 42, 42, the insides of which are provided with lowpitch threads 43, 1-3. ln this case the shafts 36A, 36tshould be soarranged that they cannot rotate, which is often of distinct advantage.Another advantage of this arrangement is that the friction on the lowpitch threads may be adjusted by means of the bolts shown at 45.

F ig. 5 shows anotherV modification in which the high'pitch screws 38A,38A are inside of the winding drum 31B and are arranged to push collars50, 50 outward. rl`he latter cannot rotate until projecting lugs 51 runout of engagement with fixed lugs 52. This insures the hi gh pitchthread acting before the low pitch thread. The lugs 52v may be made ofsuch length that the projecting lugs 5l will run out of engagement withthem before the aws engage with the guides.

'l` he above description serves to illustrate some of the modificationsand uses of my invention. lts advantages are obvious, for with it theelevator safety device is quickly brought into operation and then thecar is brought to a gradual and easy stop.

Many other modifications of my invention may be made without departingfrom its spirit. y

l have described the clamping device as on the elevator car, as that isthe usual position for such devices, but it may be placed on any desiredpart of the elevator svstem, as for example on the car counterweight.

Having described my invention, what I claim is:

l. The combination of an elevator car, a clamping device therefor, guiderails coperating with said car and device, and a differential screwhaving a high pitch thread and a low pitch thread for actuating theclamping device, cooperating parts in en gageinent with said threadswith different Adegrees of friction, the operation of said screw beingcontrolled by thedierence of threads and coperating parts, so that thelowr pitch thread is brought into operation, and the high pitch threadis held from operation by the resistanceencountered when clamping deviceengages the guide rails.

`2. The combination of an elevator car, a

Vclamping device therefor, guide rails coperating with said car anddevice, a high pitch screw and a low pitch screw, coperating partsengaging said screws with difsaid clamping device, a high pitch screwar-V ranged to move the clamping device quickly and a low pitch screwarranged to tighten` the clamping device, said screws being separate andindependently movable, and coperating parts in frictional contact withsaid screws, the independent movement of lthe screws being controlled byvtheir relative friction withsaid coperating parts, so that the lowpitch screwV is brought into operation and the high pitch screw is heldfrom operation by the resistance encountered when the clamping deviceengages the guide rails.

4. In a safety device for elevators, the combination ofV a car, aclamping device therefor, means for moving the Vclamping device Vquicklyuntil its movement meets resistance, and additional means brought intoaction by such resistance for imparting a further movement to theclamping device.

5. In a safety device for elevators the combination of a car, a clampingdevice therefor, means for moving the clamping device quickly until itsmovement meets resistance, and additional means brought into action bysuch resistance for imparting a further movement to the clamping devicewith greater force.

6. 'lhe combination of a car, guides therefor, a clamping device on thecar, a differential screw having a high pitch thread and a low pitchthread, coperating parts in frictional contact with said screw, saidscrew beingarranged to move the clamping device quickly against theguides and then to tighten it on the guides and controlled in itsoperation by the frictionV of said screw and coperating parts, so thatthe lowA pitch threadis brought into operation andthe high pitch threadis heldfrom ,operationl by the resistance encountered when the clampingdevice engages the guides.

7.. In a safety device for elevators, the

combination of a car, a guide over which.r the car is adapted to run, aclamping device i on the car, a high pitch screw arrangedv to movetheclamplng device against the guide, a low pitch screw arranged totightenthe clamping device on the guide, said low pitch screw havingfrictional connection with the y high pitch screw controlling therelative movement of the screws so that when thev low pitch screw isbrought ,into operation 75 the high pitch screw is held from-operationVby vthe frictional `resistance encountered a when the clamping deviceVengages the said guide. l 8. In a safety'device for elevators, thecombination of a car, guides over which` the car is adapted to run, aclamping device on: the car, a .high pitch screw arranged to move theclamping device against the guides, a low pitch screw arranged totighten the clamping device onthe guides, parts in frictional contactwith and cop` erating with the high pitch screw, and means for actuatingthe screws by the motion of the car, the operation of said screws being9&1?. dependent upon the friction between one of the said screws andcoperating parts, so that when the low pitch screw is brought intooperation the high pitch screw is held from operation by the resistanceencoun tered when the clamping device engages the guides.

9. In a safety device for elevators, theV combination of a car, guidesover which .the car is adapted torun, a clamping device on 1001 the car,a high pitch screw arranged Ato move the clamping device againstftheguides,v a low pitch screw arranged `to tighten lthe clamping deviceonthe guides, parts with which one of said screws cooperates and is infrictional contact, meansY for actuating ,the screws vby the motion ofthe car, and additional means for actuating the screws by hand, theoper-1 ation of said screws being controlled by the Vfriction betweensaid high pitch screw and coperating parts, so that when lthe vlow pitchscrew is brought'into operationthe high pitch screw is held fromoperation by the resistance encountered when the clamp-" ing deviceengages the guides.

10. In a safety device for elevators, the

combination of a car, guides over which the car is adapted to run, aclampingdevice on the car, a high pitch screw arranged to 12` move theclamping device against Vthe guides, al low pitch' screw arranged ytotighten the clampingA device on the guides,` parts coperating with thescrews and in frictionalfcontact with one of them,l and V means foractuating the screws by the motion of the car when the car speed reachesVVa predetermined limit,rthe operation ofsaid screws beingdependentjupon the` friction `between onek of saidiscrews andcoperat-.lSOf

ing parts kso that when the low pitch screw i is'fbrought into operationthe high pitch screw is held from operation by the resist-- anceencountered when the clamping device engages the guides.

11. i'he combination with an elevator car, l guides over which the car1s adapted to move, a clamping device on the car, a high pitch screwarranged to move the clamping device against the guides, a iow pitchscrew frictionally connected to said high pitch screw and arranged totighten the clamping Adevice on Lthe guides, thel operation of one ofsaid screws being dependent uponl the friction between said screw andcooperating gages the guides, and a governor' connected to be Vrun bythe car and arranged to actuate the screws when the speed of the carreaches a predetermined limit.

12. 1n an elevator safety device, the combination of a car, guidestherefor, clamping devices adapted to engage with the guides, right andleft hand differential screws each having a high pitch thread and a lowpitch thread, arranged to operate the clamping devices, parts coperatingwith said screws and in frictionai engagement therewith, the operationof said screws being dependent upon the friction between said screws andcoperating parts so that the low pitch. 'screws are brought intooperation and the high pitch screws are held from operation by theresistance encountered when the clamping devices engage the guides.

13. The combination of a car, guides therefor, clamping devices adaptedto engage the guides, right and left hand screws of high pitch arrangedto move the clamping devices quickly against the guides, right and lefthand screws of low pitch arranged to tighten the clamping devices on theguides, threaded members with which the high pitch screws are infrictional contact, and means for effecting the successive actuation ofsaid high and low pitch screws, the successive actuation being governedby the difference of the friction between said high and low pitchscrews, and the friction between the threaded members and high pitchscrews, so

14. In an elevator safet device the combination of a car, guidestherefor, clamping devices adapted to engage the guides, right and lefthand screws arranged to move the clamping devices quickly against theguides,

right and left hand screws of low pitch a'rl ranged to tighten'thefciampmg devices on the guides, `screw threaded members cooperforsuch operation, so that the low pitchv screws are brought into operationand the high pitch screws are held from operation bv the resistanceencountered when the clamping devices engage the guides and means foractuating the screws by hand.

15. The combination of a car, guides therefor, clamping devices adaptedto engage the guides, right and left hand screws, arranged to move theclamping devices quickly against the guides, right and left hand screwsof low pitcharranged to tighten the clamping devices on the guides,screwthreaded members coperating with the Vscrews with different degreesof friction,

said screws being dependent upon said difference of friction for suchoperation, so that the low pitch screws are brought into operation andthe high pitch screws are held from operation by the resistanceencountered when the clamping devices engage the guides and means foractuating the screws by the movement of the car.

16. fn an elevator safety mechanism, the combination with hoistwayrails, of friction members adapted to engage said rails, a device havingportions provided with threads of the same kind or direction but ofdifferent pitch, means connect-ing said threaded portions to saidfriction members, and means for automatically rotating the said deviceto lcause said friction members to be moved at first quickly and thenmore slowly by reason of difference of friction at said threads ofdifferent pitch so that the portions having low pitch threads arebrought into operation and the portions having high pitch threads areheld from operation by the resistance encountered when the frictionmembers engage said rails.

17. ln a safety device for elevators, the combination with hoistwayrails, of friction members adapted to engage said rails, a device havingdiiferential threaded portions, means connecting said threaded portionsto the said friction members, and means for automatically rotating saiddevice to cause said friction members to be moved at first quickly andthen more slowly by reason of difference of friction at said threads ofdifferent pitch so that the portions having low pitch threads arebrought into operation, and the portions having high pitch threads areheld from operation by the resistance encountered when the frictionmembers engage the said hoistway rails.

18.' In an elevator safety device, Iho'istway rails, friction membersadapted to rengage'- saidrail's, and a differential screw dependent upondifference inV friction at the screw threads to operate one of saidmembers so l resistance encountered when the that when the portions ofsaid screw having low pitch threads are brought intol operation theportions having high pitch threads are held from operation by theresistance encountered when the friction members engage the hoistwayrails.

19. In an elevator safety device, hoistway Y said screw being dependentfor its operation upon difference of friction at the yscrew threads sothat when the portion having the low pitch threads is brought intooperation the portion with the higher pitch threads is held fromoperation by the resistance encountered when the jaws engage the guiderails. t

21. In a safety device VforA elevators, the combination with hoistwayrails, of gripping jaws adapted to engage said rails, positive means foroperating said gripping jaws, and means for automatically increasing thepressure and decreasing the motion of said jaws when they come incontact with said rails.

combination with hoistway rails, of grip ping jaws adapted to be mountedon the car and engage said rails, positive means for operating saidgrippingv jaws, and means actuated by resistance of said rails to themotion of said jaws for' increasing the pres-V sure and decreasingmotion of said jaws Y when they engage the rails.

23. In a safety device for elevators, the combination with hoistwayrails, of gripping jaws adapted to engage said rails, a differentialscrew dependent upon difference 22. lIn a safety device for elevators,the

of the friction opposing the operation of said screw to operate saidgripping jaws, Y and means for automaticallyoperatmg said screw so thatwhen the part having low pitch threadsV is brought into operation the Yparthaving high pitch threads is held from operation by the resistanceencountered when the gripping jaws engage lthe hoistway rails.

24. A safety device-for elevators, comprising a drum, a safety rope forturning the drum, brakes, members connected'with the j drum, rods foroperating the brakes, said rods being connected with the members to moveendwise and means dependent upon difference of friction opposing saidmembers for first imparting a bodily endwise movement to the members androdsy so as to apply the brakes quickly on rotatingthe drum andsubsequently rotating said members in unison with the drum to impartendwise move@ ment to the rods for actuating the brakes slowly and morepowerfully, said quick operation being retarded and the slow operationeffected by the resistance encountere when the brakes are applied. Y 25.A safety device for elevators, comprising a drum, a'safety rope, theendsof which are secured to the drum, brake levers, journal bearings forthe drum, members connected with the drum, rods having heads at theirouter ends for operating the brake levers,

vsaid rods being carried by the members and connected therewith to moveendwise, and

means dependent upon difference of frictionV opposing said members forfirst imparting a bodily endwise movement to the members and rods toapply the brakes quickly on ro` tating the drum and subsequentlyrotating the said members in unison with the drum tol impart endwisemovement to the rods for actuating the brake levers slowly 'and morepowerfully, said quick operation being retarded and the slower operationeffected the resistance Vencountered when the brakes are applied.

In witness whereof, I have hereunto signed lmy name in the'presence oftwo subscribing Copies of this patent may be obtained for five centseach, by addressing the Commissioner of Patents.V

. Washington, D. C. Y

